| 摘要 |
PURPOSE: To prevent a temperature rise in a switching element by stopping an oscillating circuit without increasing circuit parts even if it is put in a no- load condition. CONSTITUTION: A main part of circuit constitution is composed of a half bridge circuit, a drive circuit 12 and an oscillating circuit 13, and a capacitor 2 is inserted between a discharge lamp 3 being a load and the negative side of DC electric power supply 1, and an electric power supply circuit is composed of a resistance 17, a Zener diode 16 and a capacitor 15 by using terminal voltage of the capacitor 2, and is supplied to the oscillating circuit 13 and the drive circuit. For electric power supply to start the oscillating circuit and the drive circuit, a capacitor 14 is connected from the positive side of the DC electric power supply. |
